rheem over temp limit error

[ga-hvac-tech]

The WHY's are the key to being successful (technically) in this business.

I suspect if you approached the faculty at your school... they could find you a current IOM (installation and operations manual) manual for that furnace. Give them the model and serial... and see if they can get it for you.

[hurtinhvac]

It's cold. It flashes an open limit before it fires. You've replaced the board and still get an open limt error before ignition. And you could not find any open safeties?

How exactly did you confirm the limit was closed?

[stuff350]

I checked with a volt meter

[hurtinhvac]

I checked with a volt meter

Seems to me you've caught the extremely rare impossibility.

Please let us know the resolution. And be very cautious when jumping around safeties. Especially if anyone you care for is living upstairs.

[Joehvac25]

I like that point you made with the parts changing hack, there isn't much of a manual that came with the unit and yes I did clear the board even changed the board.

It's a school project and they don't have a manual?

[ga-hvac-tech]

It's a school project and they don't have a manual?

Sounds like a couple of other schools I attended decades back...

[stuff350]

Waiting iom manual, to come in ill let you guys know what's wrong with it when I find out. Just also found out students have been trying to trouble shoot this unit for a year now to try to figure out what's wrong with it

[ga-hvac-tech]

Waiting iom manual, to come in ill let you guys know what's wrong with it when I find out. Just also found out students have been trying to trouble shoot this unit for a year now to try to figure out what's wrong with it

Reminds me of an experience in Aircraft maintenance school in the 1970's... Without knowing what we were doing... a few of us decided to 'fix' the bucket of bolts rotorcraft in the back lot... Did not know we had taken on one of the more complicated (and fewest parts available) rotorcraft ever built...

You guys have attacked what used to be the most advanced design of a residential furnace... Problem is... without some 'manuals'... it is literally fishing in the dark without worms.

Please do let us know what you find and learn... always glad to cheer on someone learning.

BTW: You might want to apply for PRO status based on you being a student... the LARGE majority of cool stuff at H-talk is behind the PRO door... you will be amazed. There is a section called the educational forums... would keep you glued to your computer for weeks...

[hurtinhvac]

Wonder if they are using a non OEM replacement board? Like the issues that were had when using ICM boards to replace Carrier OEM boards?

I don't know how much a manual is going to help here. Afterall; the unit is cold, the limit is closed (and was jumped), and the board still throws a limit error. All points towards board...which was replaced. But with the right board?

[stuff350]

I wonder if there was a OEM issues or a recall on the boards myself I tried to call the manufacturer but they don't like to return calls